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We developed a virtualization-based infringement incident response tool for cyber security training system using Cloud. This tool was developed by applying the concept of attack and defense which is the basic of military war game modeling and simulation. The main purpose of this software is to cultivate cyber security experts capable of coping with various situations to minimize the damage in the shortest time when an infringement incident occurred. This tool acquired the invaluable certificate from Korean government agency. This tool shall provide CBT type remote education such as scenario based infringement incident response training, hacking defense practice, and vulnerability measure practice. The tool works in Linux, Window operating system environments, and uses Korean e-government framework and secure coding to construct a situation similar to the actual information system. In the near future, Internet and devices connected to the Internet will be greatly enlarged, and cyber security threats will be diverse and widespread. It is expected that various kinds of hacking will be attempted in an advanced types using artificial intelligence technology. Therefore, we are working on applying the artificial intelligence technology to the current infringement incident response tool to cope with these evolving threats.

Consumers of information infrastructure have strong requirements for reliability of power supply. Downtime of services provided by Data Centers leads to irreversible data loss, disruption of financial and industrial enterprises and property loss. At the design stage of power systems, during feasibility study provided by comparing the alternative variants, reliability assessment is performed to estimate the possible property loss caused by failures of power equipment. For electrical installations fed by several power sources of different types and a branched distribution network, calculation of reliability parameters could be a very laborious task. Modern software make it possible to automate such calculations, considering single equipment failures and failures during the commissioning of other equipment, dependent failures of several elements, overhead lines, cables and transformers capacity, duration of manual and automatic backup switching. NEPLAN is the software that performs the tasks listed above. In education, when performing term papers and graduation theses related to design of power supply systems, using modern software improves the quality of design solutions. In this paper, NEPLAN application for reliability assessment of power supply systems is presented. It provides the alternative variants comparing. Calculations were made for Data Centers power system. The assessment presented, with minor changes, could be used for performing feasibility study of main and auxiliary power systems single line diagrams that are required for educational and professional purposes.

For gas hydrate production, gas hydrate-bearing sediments should be depressurized below the gas hydrate equilibrium pressure. Gas hydrate-bearing sediments are compacted during the depressurization process because additional effective stress evolves due to a decrease in pore pressure. The compaction of a gas hydrate reservoir can lead to several geotechnical problems such as the destabilization of the production well, settlement of the seafloor installation, or slope failure of the production site. Thus, it is important to determine the compression characteristics of gas hydrate-bearing sediments and the geotechnical behavior of gas hydrate-bearing sediments during the gas hydrate dissociation induced by the depressurization. In this study, gas hydrates were synthesized in remolded sediment samples that were originally cored from a hydrate occurrence region in the Ulleung Basin, the East Sea, offshore Korea. The volumetric strain (or change of void ratio) of gas hydrate-bearing sediment samples were measured for different gas hydrate saturations and under different vertical effective stresses. The experimental results reveal the relation between compression (or the slope of a normal consolidation line) of gas hydrate-bearing sediments and gas hydrate saturation. Experimental data for compression indices of gas hydrate-bearing sediments can be applied to numerical modeling for a geotechnical stability analysis of gas hydrate-bearing sediments.

Femtosecond light pulses tunable from 600–760 nm are generated by fequency doubling of an optical parametric oscillator in a Lithium Triborate crystal. The phase-matching bandwidth is shown to be the main limitation for harmonic generation of fs-pulses. By a dispersive element the phase-matching bandwidth and the conversion efficiency can be enhanced.

A soft switching quasi-parallel resonant DC-link (QPRDCL) inverter with improved PWM capability has been recently presented. The circuit has the minimum voltage stress of the devices and provides the flexibility of selecting the on/off instants of the resonant link, resulting in improved PWM capability. In this paper, the operational principles and the detailed analysis of the QPRDCL inverter are presented for the resonant components design and the inverter control. An SVPWM with optimal vector sequence suitable for the QPRDCL inverter is also presented through the comparisons among five different modified space vector PWM (SVPWM) techniques classified by the voltage vector sequences. The performance of the selected optimal SVPWM is verified by the experimental results.

We discuss the constraints on the mass of the lighter top squark from B 0 - B 0 mixing in the minimal supersymmetric standard model. A light top squark whose mass is less than half of the Z 0 -boson mass has not yet been excluded from direct search experiments at LEP. However, the existence of the light top squark may exceedingly enhance B 0 - B 0 mixing, owing to the box diagrams exchanging the charginos and the up-type squarks. We show that for a sizable region of parameter space the light top squark contribution to B 0 - B 0 mixing becomes the same order of magnitude as the standard W -boson contribution. Taking into account the experimental results for B 0 - B 0 and K 0 - K 0 mixings, the existence of the light top squark is excluded in an appreciable region of the parameter space which LEP experiments have not ruled out.

A static VAr compensator (SVC) using a three-level GTO voltage source inverter (VSI) is presented for high-voltage, high-power applications. The three-level VSI has lower harmonic components and higher DC-link voltage than the two-level VSI and thus can be operated at lower switching frequency (f/sub sw/

We analyze the predictions for CP asymmetries in B 0 -meson decays within the framework of the supersymmetric standard model (SSM). It is pointed out that owing to sizable new contributions to B d 0 − B 0 d and K 0 − K 0 mixings, the experimentally allowed range for the CP -violating phase δ of the Cabibbo-Kobayashi-Maskawa matrix may be different from the one obtained in the standard model (SM). This has important effects on the allowed values of CP asymmetries in B 0 -meson decays and on their correlations. We calculate the ratio R of the SSM and the SM contributions to the B 0 d– B 0 d mixing parameter x d and discuss in detail the ranges of R and S which are consistent with the experimental values of x d and the CP violation parameter ϵ for K 0 – K 0 mixing. The CP asymmetries are predicted to have values different from the SM_predictions in sizable regions of parameter space. We also discuss the SSM predictions for B 0 s – B 0 s mixing.

We show that in the supersymmetric standard model (SSM) box diagrams mediated by charginos and up-type squarks may give large contributions to $\BB$ and $\KK$ mixings. This is due to the fact that a heavy top quark mass allows large mass differences among the up-type squarks, which leads to a less efficient cancellation among the different squark diagrams. If the ratio of the vacuum expectation values of the Higgs bosons is of order of unity, box diagrams mediated by charged Higgs bosons also contribute appreciably. For sizable regions of the SSM parameter space, the SSM contributions could be sufficiently large to affect significantly the evaluation of the CKM matrix from the experimental values of the mixing parameter $x_d$ and the $CP$ violation parameter $\epsilon$.

A recently proposed circuit P-Q transformation is used to analyze a three-phase controlled-current PWM rectifier. The DC operating point and AC transfer functions are completely determined. Most features of the power converter are clearly interpreted. They are: (1) the output voltage can be controlled from zero to maximum; (2) the system is equivalently an ideal current source in the steady state; (3) the system can be described as linear circuits; and (4) the input power factor can be arbitrarily controlled within a certain control range. >

A new inductive power transfer system (IPTS) with narrow rail width and large air-gap for electric vehicle (EV) is proposed in this paper. By a new core structure, the orientation of magnetic flux is alternating along with the road. Hence, the proposed IPTS with narrow rail width, 10 cm, and large air-gap, up to 20 cm, can be implemented for EV. The power supply inverter uses 440 V, 3phase input and supplies 20 kHz output current. To null the high voltages of power rail and pick-up and to transfer maximum power to vehicles, resonant capacitors are inserted to each side of the rail and the pick-up. The test results show that the maximum output power is 35 kW and the maximum efficiency is 74 % at 27 kW output. The proposed IPTS is found to be adequate for EV which can freely drive on the road by picking up the power from the underground power supply rail.

In this paper, 3 generations of OLEV (On-Line Electrical Vehicle) are introduced. The 1st generation of OLEV is conventional E-type structure. The air gap of the 1st generation is 1cm and the input to output power efficiency is 80% with 3 kW output power. The ultra slim U-type mono rail structure is applied to the 2nd generation of OLEV. This structure is applied to the OLEV bus which achieves 52 kW output power with 72% efficiency at 17 cm air gap. SUV (Sports Utility Vehicle) equipped with the 3rd generation of OLEV named ultra slim W-type (dual rail structure) accomplished 15 kW/pick-up and 71% efficiency at 17 cm air gap

We demonstrate a terahertz wave imager with an acquisition speed at 3 frame-per-second by implementing a scanning mirror. Moving neither object nor terahertz source opens the possibility of a large area scanning at video rate.

The first demonstration of THz imaging by Hu and Nuss has stimulated many suggestions for applications ranging from biomedical imaging to semiconductor device inspection. However, many applications demand a microscopic resolution. For instance, THz imaging of biological cells would require submicron spatial resolutions because many cells have dimensions of the order of 10 /spl mu/m. Even finer resolutions would be required in semiconductor technology where today many devices are smaller than 1 /spl mu/m. Such resolutions are not easy to reach with THz technologies, because of the long wavelength of THz radiation (1 THz corresponds to a wavelength of 300 /spl mu/m). Many works took up the challenge to reduce spatial resolutions down to the 1 /spl mu/m barrier and recently our group demonstrated a resolution of 150 nm.

Chirped Pulse Amplification (CPA) is widely used for generating high-energy femtosecond pulses. This is most commonly done with a solid-state Ti:Sapphire crystal through a free-space optical path. The high energy density in the crystal and the precise optical path required with the use of bulk optics make it difficult to design a simple system with good stability and beam quality over the environmental conditions typically encountered in the manufacturing environment. A CPA system using fiber architecture reduces the need for precise beam guiding since the light follows the fiber. The pump energy is more evenly distributed along the length of the amplifier fiber, reducing the thermal dissipation that is required (no water chiller is required) and improving the overall efficiency. The fiber architecture also produces a superior quality beam that does not require great care to maintain. IMRA's latest FCPA μJewel uses the inherent advantages of the FCPA architecture, along with extensive engineering, to produce a compact and stable femtosecond fiber laser system. Its high repetition rate and stable performance enables applications that were difficult to achieve previously. This paper will review the general design architecture of the FCPA μJewel and discuss several applications.

High average power single-mode fiber lasers have attracted significant attention as alternatives to conventional solidstate lasers owing to their relative high brightness, compactness and robustness. Likewise the turn-key operation of industrially qualified ultrafast fiber oscillators is well established. In recent years the convergence of reliable ultrafast fiber oscillators, high brightness pump diodes and high power fiber amplifiers has enabled ultrafast fiber lasers to surpass ultrafast solid-state lasers in terms of average power. While fiber lasers have generally not been able to match the ultrashort pulse energies produced by solid-state lasers, careful management of nonlinearities can overcome the conventional B-integral limit of π thereby permitting stable operation of practical ultrafast fiber lasers with pulse energies approaching the milli-Joule level. Here we review modes of nonlinear propagation in fibers which have enabled increases in ultrashort pulse energies from nano-Joule to milli-Joule levels, namely: solitons, similaritons and cubicons. As an example of a practical high energy ultrafast fiber laser, we demonstrate a cubicon Yb fiber chirped pulse amplification system producing 550 fs pulses with 50 μJ at >15 W.

Recent work in frequency-conversion of pulsed fiber-amplifiers is reviewed. Design criteria of frequency converters for fiber sources in operating the wavelength range between 1 um and 2 um are discussed.

We review high power and high energy ultrafast fiber amplifiers. An Yb-fiber chirped pulse amplification system employing cubicon pulses producing sub-650 fs pulses at >100 muJ and >15W is presented.

The generation of stretched 20 pJ pulses with 200 kW peak power is demonstrated in an in-line Yb fiber chirped pulse amplification system at a repetition rate of 50 kHz. The pulses are compressible down to 400 fs using nonlinear cubical dispersion compensation.

Summary form only given. We present the highest radiation frequency, observed by far, emitted by coherent longitudinal optical (LO) phonons in III-V compound semiconductors. The results reveal the bare coherent phonon radiation in coexistence with background collective charge carrier oscillations in doped samples. We discuss differences in probing via THz radiation from the optical experiment scheme like time resolved reflectivity change.

Summary form only given. The recent development of coherent terahertz (THz) measurement technique in the time domain has opened a way to study coherent light-matter interaction in the infrared frequency range. By using free-space electro-optic sampling technique broadband detection up to 37 THz has been demonstrated. We report on the time-resolved coherent waveform of subpicosecond infrared pulse in the reststrahl bands of polar semiconductors. We observe strong oscillations at a frequency near longitudinal optical phonons in the reflection. The damping time constants of the oscillations are shown to be comparable to those of coherent phonons. Analysing the data in different time windows gives us dynamic information on the reststrahl band optical property mediated by phonons.

We present a compact THz measurement system in a portable size integrated with a femtosecond fiber laser. We demonstrate the feasibility of application of this portable and stand-alone unit for spectral characterization of chemicals. We have performed experiments in liquid chemicals. Especially, we found unique feature of transmission properties of isopropanol in the frequency range of sub-THz. Furthermore, in a whisky sample we observe an overall transmission rate of 20 % for sub-THz pulse through a cell with a thickness of 1 mm which contains 60 % of liquid water.

The circuit D-Q transformation is used to analyze a three-phase, current-source, pulse-width modulated (PWM) rectifier. The DC operating point and AC transfer functions are completely determined. Most features of the converter are clearly interpreted. The output voltage can be controlled from zero to maximum. The system is equivalently an ideal current source in the steady state and can be described in terms of linear circuits. The input power factor can be arbitrarily controlled with a certain control range. >

A novel static VAr compensator (SVC) system using a three-level inverter is proposed for high-voltage and high-power applications. A general and simple model for the overall system is obtained using the circuit DQ-transform, and DC and AC analyses are performed to characterize the open-loop system. Using the proposed model, a novel control method which controls both the phase angle and the modulation index of the switching pattern simultaneously is suggested to provide fast response of the SVC system without using the independent voltage source. Predicted results are verified by computer simulation. >

A multilevel PWM (pulse-width-modulated) voltage source inverter, especially a five-level one, is introduced to obtain a static VAr compensator (SVC) as a large-scale power source. The three phase SVC is modeled using circuit DQ transformation and completely analyzed including DC and AC characteristics. Through experimental results for a 5 kVA SVC, the validity of the analyses and the feasibility of the VAr compensation system are shown for high-power applications. >

Femtosecond coherent phonon experiments are performed on a series of GaAs/Al/sub x/Ga/sub 1-x/As multiple quantum wells (MQWs) with varying x, at fixed well and barrier width of 100 /spl Aring/. For x=0.2, we have found clear beating in time domain. Fourier transformation reveals two distinct peaks at the LO and TO phonon positions, which is indicative of bulk-like plasmon-phonon oscillations in the growth direction. This is surprising, for the supposed carrier confinement due to the relatively large barrier width has been thought to forbid such oscillations. At x=0.5, little beating is seen and only the LO phonon frequency is found in Fourier transformation), in agreement with earlier results on a series of samples with fixed x=0.35. Our results are in agreement with the recent realization of the existence of anomalously large well-to-well coupling of carriers through thick AlGaAs barriers. In addition, for bulk-like, growth-direction plasmon-phonon oscillation to be possible, we believe that optical phonons also should be able to penetrate the barrier and couple with the phonons in the next well. Such a propagating phonon model has been proposed. Finally, our barrier and x-dependent studies show that the growth-direction plasmon-phonon coupling is a more sensitive function of x than of the barrier width.

This paper proposes a new control method of static VAr compensator (SVC) with a three-level inverter to control reactive power with fast dynamics while maintaining DC side capacitor voltage constant. Firstly, using the circuit DQ-transformation, a general and simple model of SVC with a three-level inverter is obtained, and DC and AC analyses are carried out to characterize the open-loop system. Based on the transfer function matrix of the system, modulation index control for reactive power compensation and phase angle control for DC side voltage regulation are designed. By inserting feedforward path to the voltage regulation loop the modulation index is successfully decoupled from the capacitor voltage whereby fast dynamics are achieved. The experimental results confirm the theoretical analyses and control method. >

We report penalty-free 10 Gb/s single-channel transmission with co-pumped distributed Raman amplification using a novel high power, low RIN (relative intensity noise) multimode 14xx DFB pump. No penalty from pump to signal RIN transfer was observed up to 5 dB of co-pumped Raman gain. More than 200 mW from a single DFB pump was launched into the fiber without any SBS (stimulated Brillouin scattering).

Summary form only given. We have demonstrated the first all-fiber high-energy/power coherent pulse amplifier system based on Yb-doped fibers. Microjoule femtosecond pulses have been obtained at MHz-repetition rates. Achieved pulse durations and output powers constitute a significant improvement over the corresponding characteristics of Er-doped fiber amplifiers.

We present an investigation of coherent mid-infrared pulse measurement system using free-space electro-optic sampling technique. A series of nonlinear materials are investigated for the nonresonant optical rectification and electro-optic sampling for the generation and detection, respectively. A sampling bandwidth up to 40 THz is achieved. For spectroscopic application we present THz field radiation by optically excited coherent phonons in the mid-infrared frequency range. We compare the THz radiation under extremely different excitation conditions. The comparison shows the THz radiation property of the resonantly driven phonons in the surface field layer. Furthermore we investigate the coherent reststrahl band reflectivity in the time domain. Unexpectedly strong oscillations are observed near the longitudinal-optical phonon frequency. This THz waveform is discussed with the reststrahl band dispersion of the reflectivity.

The investigation of quantum coherence excited by femtosecond laser pulses is one of the central topics in quantum optoelectronics. Up to now, most investigations in semiconductors and semiconductor quantum structures deal with quantum coherence of excitonic states. For two reasons the quantum coherence of continuum states has not been anticipated for a long time due to i) the expected high momentum scattering rates of continuum states and ii) the dispersion of the valence and conduction bands, which gives rise to a strong "inhomogeneous" broadening of the band-to-band transitions. Recently, optically excited quantum coherence has been observed, which was attributed to the phase coherence of continuum states in the conduction band. These observations include Bloch oscillations in superlattices [1,2] and free-electrons in Landau levels [3]. Most recently, quantum coherence in the valence band has been observed in GaAs quantum wells [4] and bulk GaAs [5]. Here, we report on the observation of quantum coherence of the first heavy and light hole subbands in a GaAs quantum well under excitation above the fundamental excitonic transitions [4].

Since the first time-resolved observation of coherent phonons in semiconductors [1], the excitation of coherent lattice vibrations in solid states has attracted considerable interest due to the information, which can be obtained from these kind of experiments not accessible by other experimental techniques. We discuss two recent achievements on the observation of the nonlinear dynamics of the coupled phonon-carrier system by pump-probe reflectivity spectroscopy using femtosecond laser pulses.

Femtosecond time resolved coherent phonon oscillations are observed for the first time through impulsive stimulated Raman scattering (ISRS)/1/ in semiconductor Ill-V-compounds. Individual cycles of the phonon oscillations as well as the vibrational dephasing are demonstrated via a modulation of the time resolved reflectivity signatures through the electro-optic effect. The observed linear behaviour of oscillation amplitude on pump intensity confirms the excitation of coherent longitudinal polar optic phonons with a single femtosecond pulse via ISRS in GaAs, InP and AIGaAs. The macroscopic electric field associated with the lattice vibrations is measured via the electro-optic effect. This is confirmed through the distinct variation of reflectivity signal modulation versus relative orientation of probe beam polarization and crystal orientation in our pump/probe experiments.

A penalty-free 10 Gbit/s single-channel transmission with co-pumped distributed Raman amplification using novel high power, low relative integrity noise (RIN), multimode 14xx nm distributed feedback pump is reported. No penalty from pump to signal RIN transfer was observed with co-pumped Raman gains up to 6 dB large effective area fibre (LEAF). In contrast, 0.5 dB penalty was observed with a fibre Bragg grating stabilised pump at 6 dB of Raman gain.

We present time-domain transmission imaging of an opaque structure in pork-fat tissue obtained with a terahertz (THz) field sampling technique. Compared with imaging with near-infrared pulses, the terahertz sampling technique shows significantly enhanced contrast, as a result of low scattering. For enhanced spatial resolution, we show mid-infrared THz imaging of onion cells. Water absorption of THz pulse in muscle tissues is discussed.

Dispersion-compensated fully integrated Er and Yb femtosecond fiber oscillators are described. Yb MOPAs produce 100 fs pulses at repetition rates of 60 MHz with average output powers up to 200 mW. Er MOPAs generate 100 fs pulses with average output powers up to 100 mW.

Carrier envelope phase locking of a frequency comb based on an in-line low-noise Er fiber system is demonstrated. The repetition rate and the carrier envelope offset frequency are locked by two phase locked loops over several hours.

We present our recent application of the coherent mid-infrared measurement technique for phonon spectroscopy. We investigate the dynamics of phonons interacting with THz radiation. First, we excite coherent LO phonons using ultrashort near-infrared laser pulse. The THz radiation field emitted by coherent phonons is detected in the Fresnel geometry under different excitation conditions in different semiconductors. The results are discussed in terms of the dynamics and amplitude. We discuss results in different samples, i.e., semi-isolating and doped, under different optical excitation conditions. Furthermore we use coherent time-domain optics to study dielectric response dynamics in the reststrahl band. By analyzing the time-domain THz field reflectivity near the phonon frequencies of materials we demonstrate observation of a quantum kinetic behavior of the lattice dielectric response in a simple coherent optics scheme.

We present in this article the recent development of the measurement technique for coherent free-space THz field and applications in the mid-infrared range. The technique is based on the second-order nonlinear optical interaction both for the generation and for the detection of THz pulse. Particularly the detection process based on free-space electro-optic sampling gives us a possibility to timely trace directly the ultrabroad band coherent THz field unparalleled by other technique. Using an ultrashort laser pulse our measurement system is feasible to measure the ultrashort THz pulse with a bandwidth up to 40 THz. We present a detailed comparative study on the generation and detection using different nonlinear material. We demonstrate applications of the coherent THz technique for time-resolved semiconductor spectroscopy, time-domain imaging with high spatial resolution and broad band refractive and absorptive characterization of material in the mid-infrared range.